Tucannon PA 34.1-34.2 Design

The Columbia Conservation District (CCD) sponsored the Tucannon PA 34.1 - 34.2 Design project to develop preliminary designs. Project is located in Columbia County, in the Tucannon River minor spawning area and priority restoration reach between river mile 11.4 and 12.9. Project area has recently been enrolled in USDA Conservation Reserve Enhancement Program. Project reach supports Endangered Species Act listed Snake River Spring Chinook- juvenile over wintering/migration, Snake River Steelhead-spawning/rearing/overwintering and migration, Snake River Fall Chinook- spawning/rearing and Bull Trout overwintering/migration and designated as critical habitat for Bull Trout by US Fish and Wildlife. Washington Department of Fish and Wildlife completed the Tucannon Juvenile Salmonid Survival and Habitat Utilization study, project #15-1322 (2019), identifying stream reaches where overwinter juvenile mortality is high. This project is located in a priority reach to address juvenile salmonid overwintering habitats.

Goals included developing designs that addressed habitat limiting factors identified in the Draft Tucannon River Habitat Restoration Prioritization and Conceptual Restoration Plans (Anchor 2020). Design goals included enhancing instream complexity/diversity, floodplain connectivity, sediment sorting and storage and pool development supporting various salmonid life cycle needs. Completed designs include landowner property management objectives and limitations.

Project goals: Increase juvenile spring ESA listed Snake River Chinook and steelhead overwintering habitats, improve spawning conditions for ESA Snake River fall Chinook, and improve winter rearing and adult holding habitats for migratory bull trout. The design results inculde a 180 foot riparian buffer, addition of large wood structures in channel. By increasing river complexity, connecting available floodplain, creating a higher pool frequency and promoting increased sediment sorting and distribution, the CCD aims to improve geomorphic processes and create suitable habitat that will support slamonids